1. Geog 405: Advanced Spatial Analysis © J.M. Piwowar1Spatial Data Models Characteristics of Raster Data Longley et al., 2001. Geographic Information Systems and Science. Wiley.

2. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar2Spatial Data Models  How do we represent spatial information in a computer?  The rules to convert real geographical variation into discrete objects.

3. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar3Spatial Data Models

4. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar4Spatial Data Models Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

5. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar5Spatial Data Models Aronoff, 1993. Geographic Information Systems: A Management Perspective. Ottawa : WDL Publications.

6. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar6Spatial Data Models The Vector Data Model  Feature Representation  points  vertices  nodes  label points  lines  lines  arcs  areas  polygons Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

7. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar7Spatial Data Models The Raster Data Model  Feature Representation  all geographic features - points, lines, areas - are represented by grid cells  grid resolution - the minimum linear dimension of the smallest unit of geographic space sampled Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

8. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar8Spatial Data Models Raster Data Layers Lo & Yeung, 2002. Concepts & Techniques of Geographic Information Systems. Prentice-Hall.

9. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar9Spatial Data Models The Raster Data Model http://www.awi-bremerhaven.de/GEO/Marine_GIS/Principles_GIS.htm  Field representation  Object representation

10. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar10Spatial Data Models Raster Resolution 30 m resolution 3 m resolution 0.6 m resolution

11. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar11Spatial Data Models Raster Resolution Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

12. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar12Spatial Data Models Raster Resolution 30 m resolution 625 cells 3 m resolution 62,500 cells

13. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar13Spatial Data Models Raster Advantages Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

14. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar14Spatial Data Models Raster Disadvantages Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

15. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar15Spatial Data Models Vector Advantages Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

16. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar16Spatial Data Models Vector Disadvantages Davis, B.E., 2001. GIS: A Visual Approach (2nd ed.). Albany, NY: OnWord Press.

17. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar17Spatial Data Models Vector vs. Raster  Vector  the location of each vertex needs to be stored explicitly  sparse partitioning of geographic space  Raster  the geographic location of each cell is implied by its position in the cell matrix  complete partitioning of geographic space

18. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar18Spatial Data Models Vector vs. Raster  Vector  provides for precise positioning of features in geographic space  intuitive representation of geographic space  Raster  the cell size determines the resolution at which the data are represented  linear features are hard to represent

19. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar19Spatial Data Models Vector vs. Raster  Vector  more difficult to understand  some types of analysis can be difficult  Raster  conceptually simple data structure  raster algorithms are often simpler and faster

20. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar20Spatial Data Models Vector vs. Raster  Vector  compact file sizes  very large vector databases have been built for a variety of purposes  Raster  large file sizes  much new data come from remote sensing image analysis

21. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar21Spatial Data Models Spatial vs. Temporal Resolution Visual Learning Systems, 2003.

22. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar22Spatial Data Models Spatial vs. Temporal Resolution Visual Learning Systems, 2003. 0.62 m resolution; 2002 30 m resolution; 2000

23. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar23Spatial Data Models Raster Attributes Lo & Yeung, 2002. Concepts & Techniques of Geographic Information Systems. Prentice-Hall.

24. Geog 409: Advanced Spatial Analysis & Modelling © J.M. Piwowar24Spatial Data Models Common Raster Data Formats  TIFF (Tagged Image File Format)  JPEG (Joint Photographic Editors Group)  GIF (CompuServe Graphics Interchange Format)  MrSID (Multi-resolution Seamless Image Database)  BIL (ERDAS Band-Interleaved-by-Line Format)  IMG (could be any type of image)